body {
  font-family: 'Tahoma', sans-serif;
  direction: rtl;
  background: #f4f4f4;
  margin: 0;
  padding: 0;
}
header {
  background: #111;
  color: #fff;
  padding: 20px;
  text-align: center;
}
nav {
  margin-top: 10px;
}
nav a {
  margin: 10px;
  text-decoration: none;
  color: #ffeb3b;
  font-weight: bold;
}
main {
  padding: 20px;
  text-align: center;
  font-size: 18px;
}